Symmetry of Gd Excretion

A delayed scan (about 10 minutes after administration of contrast material) can be used to assess the excretory function of kidneys (Fig. 19). On older scanners with longer echo times, the highly concentrated Gd in collecting systems may shorten the T2 so much that the MR signal dephases faster than the TE, thereby reducing the utility of the delayed scan. However, on state-of-the-art MR scanners with TE < 1 msec, it is possible to capture the signal from highly concentrated Gd in the urine. Asymmetrical signal intensity in collecting systems is a reliable indicator of unilateral renal dysfunction that may result from ischemia [32]. In the ischemic kidney, glomerular filtration of Gd is maintained by activating the renin-angiotensin system. But there is greater reabsorption of water for maintenance of high blood pressure. This results in hyperconcentration of Gd contrast within urine on the ischemic side (Fig. 20a, b) [32].

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Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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